Heretofore fibrous glass substrates such as glass fabric have been coated with compounds which serve as coupling agents or bonding agents between the glass and a thermosetting resin applied thereon. U.S. Pat. No. 3,682,975, issued Aug. 8, 1972, discloses the use as coupling agents of silyl epoxyalkylamines of the formula: ##STR5## WHEREIN A is selected from the group consisting of hydrogen, alkyl, aryl, alkaryl and aralkyl;
m is an integer from 0 to 3; PA1 n equals the quantity (3-m); PA1 Each R and R' is selected independently from the group consisting of alkyl, alkoxyalkyl, aryl, alkaryl, and aralkyl; and PA1 Z is a divalent organic radical. PA1 X is chlorine or bromine, PA1 R.sub.1 is hydrogen, alkyl of 1 to 5 carbon atoms or ##STR7## and Z is selected from the group consisting of ##STR8## where R.sub.2 at each occurrence is independently hydrogen or alkyl of 1 to 5 carbon atoms, and PA1 p is an integer of 1 to 4, and ##STR9## where m and r are integers of 1 to 3, PA1 R.sub.2 has the meaning given above, and PA1 Y is --S-- or --O-- PA1 n is an integer of 1 to 4.
These compounds are prepared by reacting a substituted silyl amine with an epihalohydrin to form a substituted silyl-3-halo-2-hydroxyalkylamine and then subjecting this intermediate compound to dehydrohalogenation with ring closure to form the desired silyl epoxyalkylamine compound. While such epoxy compounds are good coupling agents for fibrous glass substrates, the dehydrohalogenation step is difficult and expensive.